Thumb three

Polydactyly is the most common congenital malformation of the hand, which mostly occurs on the radial side of the hand and sometimes merges with other malformations. It can be divided into three types clinically: ① Excess fingers only have soft tissue and no bones. ② There are some phalanges and some tendons in the extra fingers, which is a functionally defective finger. ③ It has a complete palm and phalanx, and its functions are relatively complete. It is difficult to distinguish which finger is multi-finger. Wassel divides the radial multiple fingers into seven types: type I, distal phalanx bifurcation; type II, distal phalanx complete repeat; type III, distal phalanx repeat; type IV, complete proximal phalanx; type V, section One metacarpal bifurcation and the proximal phalanx base of the repeated fingers form joints respectively; type VI, the metacarpal repeats, the thumb completely repeats; type VII, the normal thumb is a three-section phalanges or part of a three-section phalanges.